Questions:

1.

The mean and standard deviation of a data set are given as 35 and 7 respectively. If 5 is added to each value of the data set to make a new data set, find the mean and standard deviation of the new data set.

2.

State two ways in which panel surveys differ from longitudinal surveys.

3.

A random variable X is normally distributed with a mean of 90 and a standard deviation

of 7. What limits of X would include the middle 65% of the possible values of X?

4.

From a population that is normally distributed with unknown mean and a standard

deviation of 1.25, a sample of size 36 is taken.

(i) What is the standard error of the sample mean?

(ii) What is the probability that the sample mean is within 0.5 units of the population mean?

(iii) How large a sample size must we take to be 98% confident that the sample mean is within one-half of the population mean?